Melt spinning apparatus

ABSTRACT

Melt-spinning assembly in which opposed heat transfer surfaces of pack are gripped by heat transfer surfaces of setting by relative displacement of the latter surfaces, preferably transversely to the direction of movement of the filaments.

Unite States atent [191 Coates et a1.

[ MELT SPINNING APPARATUS Inventors: Ronald Bell Coates; Ralph .Iohn

Basil Marsden; Frederick Arthur Smith; Gerald Towle, all of l-larrogate, England Assignee: Imperial Chemical Industries Limited, Millbank, London, England Filed: Aug. 28, 1972 Appl. No.: 284,376

Foreign Application Priority Data Sept. 14, 1971 Great Britain 42772/71 US. Cl. 425/464, 425/378 Int. Cl Dold 3/00 Field of Search 425/378, 382.2, 192, 464; 164/283, 338; 249/79, 82

1 Aug. 20, I974 [56] References Cited UNITED STATES PATENTS 3,500,499 3/1970 Goossens 425/192 FOREIGN PATENTS OR APPLICATIONS 436,557 11/1967 Switzerland..... 425/464 467,652 12/1951 Italy 164/283 Primary ExaminerRobert D. Baldwin Attorney, Agent, or Firm Roderick B. Macleod; Stephen D. Murphy; Thomas J. Morgan [57] ABSCT Melt-spinning assembly in which opposed heat transfer surfaces of pack are gripped by heat transfer surfaces of setting by relative displacement of the latter surfaces, preferably transversely to the direction of movement of the filaments.

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MELT SPINNING APPARATUS The present invention relates to the melt spinning of fibre-forming synthetic polymers to form fibres or filaments. More particularly the present invention relates to a removable melt-spinning pack and setting.

According to the present invention we provide a melt-spinning assembly comprising a pack with two opposed heat transfer surfaces and a pack setting adapted for heating to a controllable temperature and containing a socket adapted for receiving the pack, the socket having two opposed heat transfer surfaces adapted for relative displacement whereby area contact is effected with the heat transfer surfaces of the pack and the pack is gripped. Preferably the gripping of the pack is effected by forces in a direction transversely to the direction of movement of the filaments.

Relative displacement, in addition to linear displacement may include angular displacement whereby parallelisation of contacting surfaces may be ensured to achieve close contact.

In the term pack we include at least a spinneret and a heat exchanger. The pack may also include, for example, a filter, a gauze and a static mixer.

Examples of suitable means for providing relative displacement are: a. a hollow platten is connected to a chamber in the setting by flexible ducts through which heat transfer fluid may be passed. A surface of the platten constitutes one of the heat transfer surfaces of the socket, and the platten is urged towards the other heat transfer surface of the socket by jacking means,

b. a heat transfer surface of the socket is borne on a wedge the second surface of which contacts the body of the setting either directly or through a conducting member; the first surface of the wedge contacts the heat transfer surface of the pack which may be continuous with the pack body or borne on a conducting member in contact with the body of the pack. The contact surface of the conducting member and the body of the setting or of the conducting member and body of the pack may be a portion of the surface of a cylinder or a portion of the surface of a sphere. The wedge may be simple or may be compound allowing alteration of the included angle when the wedging action is exerted to effect the desired relative displacement.

An example of apparatus according to method (a) is illustrated in FIG. 1, which shows a vertical section of a setting and pack.

Referring to FIG. 1, a setting (I) has socket (2) into which pack (3) may be inserted. Pack (3) has opposed first (4) and second (5) heat transfer surfaces. The socket (2) has opposed first (6) and second (7) heat transfer surfaces, second heat transfer surface (7 being a surface of the movable platten (8), in which is chamber (9) having contractible tubes (10) and (11) communicating with chamber (12) in setting (1). A heat transfer fluid, maintained at a suitable temperature, is circulated through chamber (9) and chamber (12) by means not shown. A screw (13) operates in a threaded hole in setting (1). In operation, pack (3) is inserted in the socket (2) and screw (13) is rotated clockwise thus exerting an urging force on the platten (8) towards the left in FIG. 1, thus effecting relative displacement of surfaces (6) and (7) and close contact facilitating good heat transfer between heat transfer surfaces (4) and (6) and between heat transfer surfaces (5) and (7 The application of pressure by the screw at a single location allows angular displacement of the platten allowing parallelisation of surfaces (5) and (7).

The feed of fibre-forming polymer melt is through an aperture (14) in the first heat transfer surface (6) which, when the pack (3) is in position, communicates with an aperture (15) in the pack (3), leading to feed pipe (16), which feeds spinneret (17). Thus the urging together of the pair of first heat transfer surfaces also facilitates the formation of a liquid-tight joint. A circular gasket of about 243 inch square section of poly(tetrafluoroethylene) was used to ensure formation of the liquid tight joint. The gasket was accomodated in recesses cut in the pack (3) and the setting (1). Very little of the jacking force was used to compress the gasket and the reduction in heat transfer area was small.

An example of apparatus according to method (b) is illustrated in:

FIG. 2, which shows a vertical section of a setting and pack.

Referring to FIG. 2, a setting (I) has socket (2) into which the pack (3) may be inserted. Pack (3) has opposed first (4) and second (5) heat transfer surfaces. The socket (2) has opposed first (6) and second (7) heat transfer surfaces. The second heat transfer surface (5) of the pack (3) contacts surface (7) of wedge (20), the second surface of which (21) contacts surface (22) of conducting member (23). The second surface (24) of conducting member (23) in turn contacts surface (25) of the body of the setting (I). A jacking screw (26) may be used to exert pressure downwards (according to FIG. 2) which on reverse screwing withdraws the wedge (20). In operation pack (3) is inserted in the socket (2) and, after assembly of the other parts, the wedge (20) is urged downwards (according to FIG. 2), thus effecting the desired relative displacement of heat transfer surfaces (6) and (7 and effecting the desired contact with the heat transfer surfaces of the pack. The curvature of the surfaces (24) and (25) also allows angular displacement of surface (21), facilitating parallisation.

The feed of fibre-forming polymer melt is through an aperture (14) in the first heat transfer surface (6) which, when the pack (3) is in position, communicates with an aperture (15) in the pack (3), leading to feed pipe (16), which feeds spinneret (17). Thus the urging together of the heat transfer surfaces (4) and (6) also facilitates the formation of a liquid-tight joint. A circular gasket of about /s inch square of poly(tetrafluoroethylene) was used to ensure formation of the liquid tight joint. The gasket was accomodated in recesses cut in the pack (3) and the setting (1). Very little of the jacking force was used to compress the gasket and the reduction in heat transfer area was amall.

According to a preferred feature of method (b), the wedge is composite and is so constructed that the wedge angle is variable and in operation conforms to the angle between the second heat transfer surface of the pack and the second heat transfer surface of the setting. Thus, for example, the wedge may comprise two parts each of which bears one of the wedging surfaces, the two parts contacting each other in a curved surface which is a portion of a cylindrical or a portion of a spherical surface. Thus in operation the wedging angle may change while good heat transfer contact is retained between the two parts of the wedge, and the change in the wedging angle allows the wedge to conform to small deviations from the designed angle between the second heat transfer surface of the pack and the second heat transfer surface of the setting produced in routine manufacture. This angle may also change when a pack is removed from a setting and replaced by a second pack, which is a routine exercise in melt spinning. Advantageously the two parts of the wedge are slideably coupled, so as to limit relative movement other than the desired relative sliding movement which allows the desired variation in wedging angle. Advantageously the two parts of the wedge are urged slideably relatively to each other so that when no external pressure is applied the two parts of the wedge tend to take up the relative position to each other resulting in the minimum wedge angle, so that in operation pressure is applied by the wedge first at its narrowest part, progressing thereafter towards the widest part.

An example of apparatus according to this preferred embodiment of method (b) is illustrated in:

FIG. 3, which shows a vertical section of a setting, pack and wedge, wherein the wedge is in two parts each bearing one of the wedging surfaces.

Referring to FIG. 3, a setting (1) has socket (2) into which the pack (3) may be inserted. Pack (3) has opposed first (4) and second (5) heat transfer surfaces. The socket (2) has opposed first (6) and second (7) heat transfer surfaces. A wedge (30,31) is formed from parts (30) and (31) which have common surface (32), in the form of a portion of a cylindrical surface of radius 43 cm. The two parts of the wedge are slideably coupled by bolt (33) which is screwed into part (31) after passing through a hole (34) in part (30). The hole (34) is elongated in the vertical direction as seen in FIG. 3 to allow relative movement of parts (30) and (31) vertically. A jacking screw (35) may be used to exert downwards pressure on part (31) downwards pressure also being transmitted to part (30) through extension (36) bolted to part (31) and compression spring (37). When not in operation, compression spring (37) serves to urge the two parts (30) and (31) of the wedge (30,31) slideably with relation to each other so as to result in a minimum wedging angle. In operation downward pressure on part (31) results in relative displacement of heat transfer surfaces (6) and (7) and the wedging angle progressively increases until it conforms to the angle between faces (5) and (7), giving a good heat transfer between the wedge (30,31) and the pack (3) and between the wedge (30,31) and the setting (1). At the same time, the lateral pressure exerted by the wedge on the pack (3) results in the first heat transfer surface (4) of the pack (3) being forced into close contact with the first heat transfer surface (6) of the setting (1), thus ensuring good heat transfer.

The feed of fibre-forming polymer melt is through an aperture 14) in the first heat transfer surface (6) which, when the pack (3) is in position, communicates with an aperture in the pack (3), leading to feed pipe (16), which feeds spinneret (17). Thus the urging together of the heat transfer surfaces (4) and (6) also facilitates the formation of a liquid-tight joint. A circular gasket of about 1 8 inch square section of poly(tetrafluoroethylene) was used to ensure formation of the liquid tight joint. The gasket was accomodated in recesses cut in the pack (3) and the setting (1). Very little of the jacking force was used to compress the gasket and the reduction in heat transfer area was small.

An alternative method of achieving the change in wedge angle is by fabricating the wedge from a number of members each comprising a proportion of each of the wedging faces of the wedge. Each of the members is urged apart by suitable resilient means so that in operation pressure applied to the member at the wider end of the wedge is transmitted to each successive member with deformation of each member and/or of the resilient means in such a manner as to increase the wedging angle, that is the included angle of the composite unit. Within limits, local deviations of the second heat transfer surface of the pack or of the second heat transfer surface of the setting will also be taken into account by this design of wedge, since individual members of the wedge may deform to differing extents.

An example of apparatus incorporating such a wedge is illustrated in FIG. 4, which shows a vertical section of a setting, pack and wedge, wherein the wedge is compose of a multiplicity of members each comprising a proportion of each of the faces of the wedge.

Referring to FIG. 4, a setting (1) has socket (2) into which the pack (3) may be inserted. Pack (3) has opposed first (4) and second (5) heat transfer surfaces. The socket (2) has opposed first (6) and second (7) heat transfer surfaces. A wedge (40a-400) is composed of members (40a, 40b, 40c 400) each separated from its neighbour by a Belville washer (41) and each bearing heat transfer surfaces (7 and 42). A jacking screw (43) may be used to exert pressure downwards on member (40a) which is transmitted to successive members through the Belville washers (41). In operation the pressure transmitted to the various members (40a, 40b, 40c 400) causes bending of each with consequent reduction in the angle between the heat transfer surfaces (7 and 42) producing an overall reduction in the effective wedging angle (angular displacement). At the same time relative linear displacement between surfaces (6) and (7 occurs and the lateral pressure exerted by the wedge on the pack (3) results in heat transfer surface (4) of the pack (3) being forced into close contact with heat transfer surface (6) of the setting (1), thus improving heat transfer.

The feed of fibre-forming polymer melt is through an aperture (14) in the first heat transfer surface (6) which, when the pack (3) is in position, communicates with an aperture (15) in the pack (3), leading to feed pipe (16), which feeds spinneret (17). Thus the urging together of the heat transfer surfaces (4) and (6) also facilitates the formation of a liquid-tight joint. In method (b) the method used for exerting downward pressure on the wedge, for example the jacking screw shown as (26) in FIG. 2, should be such as to allow the wedge to pivot slightly about the point of application of the pressure at right angles to the plane of the paper in F IG. 2 or 3 to take up any lack of parellelism of, for example, the two opposed heat transfer surfaces of the pack.

What we claim is:

l. A melt spinning assembly comprising a pack with two opposed heat transfer surfaces and a pack setting including means for heating the pack setting to a controlled temperature and containing a socket adapted for receiving the pack, the socket having two opposed heat transfer surfaces, wherein the improvement comprises having in combination therewith means for rela- 6 tive displacement and for angular displacement of at through which heat transfer fluid may be passed. least one of said sockets opposed heat transfer sur- 3. The apparatus of claim 1 wherein a heat transfer faces, whereby said pack is gripped in close contact by surface of said socket is borne on a wedge. parallelisation of contacting heat transfer surfaces. 4. The apparatus of claim 3 wherein said wedge is a 2. The apparatus of claim 1 wherein at least one of 5 compound wedge having two parts in slideable rotatsaid heat transfer surfaces of said socket comprises a able contact.

surface of a hollow platten having flexible ducts 

1. A melt spinning assembly comprising a pack with two opposed heat transfer surfaces and a pack setting including means for heating the pack setting to a controlled temperature and containing a socket adapted for receiving the pack, the socket having two opposed heat transfer surfaces, wherein the improvement comprises having in combination therewith means for relative displacement and for angular displacement of at least one of said socket''s opposed heat transfer surfaces, whereby said pack is gripped in close contact by parallelisation of contacting heat transfer surfaces.
 2. The apparatus of claim 1 wherein at least one of said heat transfer surfaces of said socket comprises a surface of a hollow platten having flexible ducts through which heat transfer fluid may be passed.
 3. The apparatus of claim 1 wherein a heat transfer surface of said socket is borne on a wedge.
 4. The apparatus of claim 3 wherein said wedge is a compound wedge having two parts in slideable rotatable contact. 